Cloudburst totem (shaman talent)

Hello everyone.

Cloudburst Totem.

I wanted to try to fix this talent, unfortunately did not find such examples.
The bottom line is this: when using healing spells, totem aura should change amount and display, how much energy has been accumulated
When you remove the aura - manually or action ended totem should CastCustomSpell, as a percentage of mod.

SPELL_SHAMAN_CLOUDBURST = 157503, // in enum ShamanSpells

Tell me please, what need change. What add. Thanks advance.